Making electric cars less quiet

With electric vehicles on the roads in increasing numbers, the question emerges time and again: are EVs too quiet? Does the lack of an engine rumble make them a danger to others on the road?

The issue has been a persistent concern. Now, the National Highway Traffic Safety Administration (NHTSA) has taken the next step and proposed rules requiring automakers to build in sounds for their electric models when they are traveling at less than 18 miles per hour. The move is meant to reduce the risk of injury to pedestrians, who may not hear the cars nearby.

Following an earlier congressional mandate requiring a minimum sound standard for EVs, some car companies have already taken the initiative. Nissan has already developed a whirring noise for its electric Leaf model. In 2011, Ford even looked to its customers to select a sound to make its electric Focus model noisier.

The NHTSA estimates that the new regulation would prevent as many as 2,800 injuries to pedestrians or cyclists. Though the rule must go through a 60-day comment period before it is finalized, once it is in place automakers will have three years to comply with the regulation.